Hollow molded products such as plastic bottles formed by stretching and blow molding are excellent in transparency and strength as compared with hollow molded products formed by blow molding and are being extensively used as bottles for beverages and as containers for various contents.
With extension of uses, it has been desired to increase the strength of hollow molded products and provide products which have their external shape suited for the contents. In the case of bottles for carbonated beverages, a separately molded base cup is fitted on a bottom of the hollow molded product in an attempt to increase the strength of the bottom thereof.
In fitting the base cup, a device is required in which the base cup coated with an adhesive is fitted and pressed on the bottom of the hollow molded product, and after the hollow molded product is removed from the molding machine, it must be fed into the device. This procedure involves disadvantages in that much trouble is required and product loss tends to occur.
To cope with these problems, the present inventor has developed a setting device, which was described in a previously filed application now U.S. Pat. No. 4,303,381), in which a base cup is inserted into a stretching and blow mold assembly and the base cup is fitted simultaneously with stretching and blow molding of a hollow molded product. However, in the presently existing distributor, it is difficult to positively supply the required number of base cups to the setting device at all times. The distributor needs to be improved in order to meet the practical requirements, and the disadvantages noted above are not yet eliminated. At present, for large bottles for carbonated beverages, a separate device is used to fit the base cups.
Where plastic bottles or the like formed by stretching and blow molding are used as containers for fruit juice, honey, Japanese sake, etc. which require the step of heating and filling, the thermal stability needs to be improved to prevent containers from being deformed due to the thermal shrinkage when filled with heated fluid.
Even in case of polyethylene telephatalate bottles which are used as containers for carbonated beverages which particularly involve a problem in their heat resisting property but which are excellent with regard to their gas barrier property, it is partly embodied that the bottles are subjected to heat treatment to impart the heat resisting property thereto for the reason that if the heat resisting property thereof is enhanced, they can be used also as bottles for fruit juice which has a high filling temperature.
This heat treatment is accomplished by using a separate special device after a molded bottle has been removed. Therefore, the production efficiency is poor and additional labors are required, thus tending to increase the cost. In view of these circumstances, it has been desired to develop a molding machine which will not particularly increase the cost of products.
The stretching and blow molding of hollow molded products is roughly divided into two means or categories. One means is a cold parison system in which a pre-injection molded parison is heated to a molding temperature, after which it is stretched and blow molded into a hollow molded product. The other means is a hot parison system in which an injection molded parison is immediately stretched and blow molded while the parison is in a heated condition.
As one of the machines of the aforesaid hot parison system, the machine invented by the present inventor is disclosed in U.S. Pat. No. 4,105,391. The injection stretching and blow molding machine described in said patent has a rotary disk which is disposed above a machine bed leaving a work space, and about the rotary disk, there are four operating sections which respectively perform injection molding, temperature controlling, stretching and blow molding, and releasing of parisons. The machine is provided with a construction in which the aforesaid four operations are simultaneously carried out every stop of said rotary disk provided on the lower surface thereof with a plurality of neck molds for holding the injection molded parisons in a vertical direction.
The present inventor has achieved a new invention of an injection stretching and and blow molding machine, which has been developed by the person himself and is actually used as the ASB machine, in order to meet a demand as containers for carbonated beverages and a demand as containers filled with fruit juice or the like by heating.